Gear unit having a housing

ABSTRACT

A gear unit includes a housing, a trough for guiding oil and reducing losses due to splashing surrounding a circumferential section of a toothing part, particularly a gear wheel, especially in the radial and axial direction. The trough includes at least three parts, e.g., at least one bottom plate and two side walls, the bottom plate being screw-connected to the two side walls. The trough is fastened to the housing and includes an opening, particularly a channel, especially at its lowest surface area, e.g., particularly at the surface area having the greatest radial distance. In particular, during rotational movement of the gear wheel, oil is conveyed from the oil pan of the gear unit through the opening between the trough and gear wheel, especially to a position higher than the level of the oil pan. The bottom plate and the side walls are stamped bent parts.

FIELD OF THE INVENTION

The present invention relates to a gear unit having a housing.

BACKGROUND INFORMATION

It is generally known that a housing of a gear unit has bearingmountings in which the bearings for the shafts of the gear unit are ableto be accommodated, and the related forces are dissipated.

SUMMARY

Example embodiments of the present invention provide a gear unit havinga housing, which may protect the environment, particularly saveresources.

Among features of example embodiments of the present invention withregard to the gear unit having a housing are that a trough for guidingoil and reducing losses due to splashing surrounds a circumferentialsection of a toothing part, particularly a gear wheel, especially in theradial and axial direction. The trough includes at least three parts,e.g., at least one bottom plate and two side walls, the bottom platebeing screw-connected to the two side walls. The trough is fastened tothe housing and includes an opening, particularly a channel, especiallyat its lowest surface area, e.g., particularly at the surface areahaving the greatest radial distance. During rotational movement of thegear wheel, oil is conveyed from the oil pan of the gear unit throughthe opening between the trough and gear wheel, especially to a positionhigher than the level of the oil pan. The bottom plate and the sidewalls are stamped bent parts.

An advantage in this context is that with the aid of the gear wheel, oilis able to be delivered from the oil pan of the gear unit to ahigher-situated location such as a temporary storage or a collectingchannel, and thus from there, bearings and meshing gear teeth are ableto be lubricated with lubricating oil. In addition, with the aid of thetrough that, at least sectionally, correspondingly follows the contourof the gear wheel, therefore the outline of the rotating gear wheel,e.g., the cylindrical spatial area that is contacted by the rotatinggear wheel, losses due to splashing are able to be reduced. To that end,the gap between the rotating gear wheel and the trough, especially thebottom plate of the trough, must be made small. The bottom plate issituated, with its surface section facing the gear wheel, at a radialdistance that is set apart only slightly from the radial distance of thecrowns of the gear teeth of the gear wheel to the axis of the gearwheel. Therefore, the surface section of the bottom plate facing thegear wheel extends substantially in the circumferential direction and inthe axial direction, but with the exception of an opening, always hasthe same radial distance to the axis of the gear wheel, especially tothe axis of the shaft to which the gear wheel is joined in rotatablyfixed fashion.

The construction of the trough from only three parts forming it, namely,bottom plate and side walls, permits an especially cost-effectiveproduction by screw-connecting these parts.

The distance, particularly the distance in the radial direction, betweenthe bottom plate and the crowns of the gear teeth may be constant in theangle-at-circumference area covered by the trough. This is consideredadvantageous because a small gap is sufficient as distance in order toachieve the pumping action. Losses due to splashing are therefore ableto be reduced.

The bottom plate may have tab sections extending in the radialdirection, at which the side walls are screw-connected. An advantage inthis case is that the tab sections are able to be produced in an easymanner by bending a punching sheet. In addition, the tab section is ableto be aligned parallel to the side wall, e.g., perpendicular to thesurface section of the bottom plate extending in the circumferentialdirection and in the axial direction. Therefore, a simple sturdyconnection is attainable between the bottom plate and side wall. In thecase of a production series of gear units in which gear wheels ofdifferent sizes are used, a transmission ratio that is different in eachinstance is achievable for each gear unit in the production series.Consequently, however, the bottom plate must be secured at a radialdistance adjusted in each case, and thus the axially aligned screws ofthe screw connection between the bottom plate and side wall at differentradial distance, accordingly.

One side wall may have a marking, at which a bore hole is able to beplaced for leading through a screw of the screw connection. An advantagein this instance is that depending on the transmission ratio of the gearunit or size, especially the crown circle diameter, of the gear wheel, abore hole is able to be placed at the radial distance indicateddifferently in each case, and thus the trough is able to be disposed atdifferent radial distance.

The opening, especially the channel, may be bounded by the bottom plateand the two side walls This is considered advantageous because anoil-conveying opening is able to be produced in an inexpensive anduncomplicated manner.

The bottom plate and each side wall may in each instance be formed inone piece, e.g., integrally. This is considered advantageous becauseeach of the three parts is able to be produced as a stamped bent part,e.g., in a very inexpensive and uncomplicated manner. In this context,even the two side walls are able to be similarly implemented.

According to an example embodiment of the present invention, a housingis provided for a gear unit, the housing having a housing top part and ahousing bottom part, the housing top part having a frame-like supportsection on which wall sections are molded. The frame-like supportsection is formed integrally, e.g., in one piece, with the wallsections, particularly as a casting, especially as a steel casting.

An advantage in this case is that only the support section must containa lot of material, e.g., also mass, but not the wall sections.Therefore, great forces are able to be transmitted, while saving onmaterial.

The greatest wall thickness of the wall sections may be less than thegreatest wall thickness of the support section. An advantage in thisinstance is that the wall sections are able to be implemented with thinwall thickness, making it possible to realize the housing while savingon material.

The frame-like support section of the housing top part may have a firstand a second transverse rib, in particular, the transverse ribsstretching mainly in the horizontal direction, e.g., in particular,being extended further in the horizontal direction than in any directiontransverse to it. The frame-like support section includes two firstribs, the two first ribs being set apart from each other and in eachcase being joined to the first transverse rib, especially at two pointsset apart from each other, in particular, the first ribs stretchingmainly in the vertical direction, e.g., in particular, being extendedfurther in the vertical direction than in any direction transverse toit. The two second ribs are set apart from each other and in each casebeing joined to the second transverse rib, especially at two points setapart from each other, in particular, the second ribs stretching mainlyin the vertical direction, e.g., in particular, being extended furtherin the vertical direction than in any direction transverse to it. Thisis considered advantageous because especially high stability isattainable, accompanied by little expenditure for material. The reasonis that the frame-like support section has a rectangular shape, in whichthe rectangle is bent out of the plane of the rectangle at its twoopposite sides, so that the bent areas are located substantially infurther planes that are perpendicular to the plane, are set apart fromeach other, and are parallel to each other.

Each first rib and each second rib may have a lifting eye at its endarea facing away from the respective transverse rib. This is consideredadvantageous because the forces introduced into the housing duringtransport are introduced directly into the frame-like support section,and not into wall sections having thin wall thickness.

A first rib may be joined at its end area to a bar, especially a supportbar, that is joined at its other end to the end area of a second rib,the other rib being joined at its end area to a bar, especially asupport bar, that in turn is joined at its other end to the end area ofthe other second rib. In particular, the two bars are disposed inparallel and set apart from each other. This is considered advantageousbecause high stability is attainable with the aid of the bracings.

A shaft of the gear unit may be supported by a bearing in the housing, afirst part of the bearing mounting being located in the housing top partand a second part of the bearing mounting being located in the housingbottom part, the first part of the bearing mounting being implemented asa thickened section, and being joined to that area of the transverseribs at which the respective rib is also joined. An advantage in sodoing is that an additional bracing of the frame-like support section isprovided by the thickened areas.

A housing cover may close an opening in housing top part, the openingbeing surrounded by the frame-shaped support section, particularly withclearance, especially so that the frame-shaped support section does notdirectly contact the opening, but rather is set apart from the opening.An advantage in this case is that gear-unit parts are able to beinspected through the opening and maintenance work is able to be carriedout. At the same time, no lubricating oil flows out from the gear uniteither, since the opening is located on the upper side of the housingtop part.

Among features with regard to the gear unit are that it is provided witha housing, a shaft of the gear unit being supported by a bearing in thehousing, a first part of the bearing mounting being located in thehousing top part and a second part of the bearing mounting being locatedin the housing bottom part, the first part of the bearing mounting beingimplemented as a thickened section, and being joined to that area of thetransverse ribs at which the respective rib is also joined.

This is considered advantageous because high torsional stiffness andhigh mechanical stability are attainable.

Example embodiments of the present invention are explained in greaterdetail with reference to the Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an oblique view of a gear-unit housing according to anexample embodiment of the present invention for a gear unit in a firstviewing direction, the housing including a housing top part 1 and ahousing bottom part 2.

FIG. 2 shows an oblique view of the gear-unit housing in another viewingdirection.

FIG. 3 shows an oblique view of the gear-unit housing in a third viewingdirection.

FIG. 4 shows an oblique view of housing bottom part 2.

FIG. 5 shows an oblique view of housing top part 1.

FIG. 6 shows the frame-like support section of housing top part 1.

As a segment from housing top part 1, FIG. 7 shows a side wall section3, which is inserted into the frame-like support section.

As a segment from housing bottom part 2, FIG. 8 shows a wall sectionhaving a wave structure, e.g., especially a concave-convex wall section.

FIG. 9 shows oil level 90.

FIG. 10 shows a gear wheel 100 of the gear unit that is mounted inrotatably fixed manner on a shaft 101 supported in the gear-unithousing, and is at least partially surrounded by a trough secured tohousing bottom part 2.

FIG. 11 shows the trough itself in oblique view, the trough having sidewalls 102 and a bottom plate 103.

FIG. 12 shows a side wall 102 of the trough.

FIG. 13 shows bottom plate 103 of the trough.

DETAILED DESCRIPTION

As shown in FIG. 1, housing bottom part 2 is disposed below housing toppart 1. Thus, housing top part 1 is situated above housing bottom part 2in the vertical direction.

Housing top part 1 has a frame-like support section, which takes up andconducts the major portion of the forces. The remaining sections ofhousing top part 1 are formed only for the oil-tight enclosure of thegear-unit interior, e.g., are formed with thinner wall thickness thanthe support section and join closely to the support section.

Consequently, housing top part 1 as well as housing bottom part 2 areformed in shell-like fashion.

The frame-like support section of housing top part 1 has a firsttransverse rib 62. It extends mainly in the horizontal direction.

Two first ribs 61 are set apart from each other, and in each case arejoined to first transverse rib 61, particularly at two points set apartfrom each other.

First ribs 61 stretch mainly in the vertical direction, e.g., areextended further in the vertical direction than in any directiontransverse to it.

The frame-like support section of housing top part 1 also has a secondtransverse rib 62. It extends mainly in the horizontal direction.

Two second ribs 61 are set apart from each other, and in each case arejoined to second transverse rib 61, particularly at two points set apartfrom each other.

Second ribs 61 stretch mainly in the vertical direction, e.g., areextended further in the vertical direction than in any directiontransverse to it.

Each first rib 61 and each second rib 61 has a lifting eye 63 at its endarea facing away from the respective transverse rib. Thus, the gear unitis able to be picked up at the lifting eyes by hooks or cable and iseasily transportable. The forces occurring during transport areintroduced at lifting eyes 63 into the end areas and thus into theframe-like support section. Consequently, the gear-unit housing becomesonly negligibly deformed and remains undamaged.

A first rib 61 is joined at its end area to a bar 60, particularly asupport bar, which at its other end is joined to the end area of asecond rib 61. In the same manner, the other rib 61 is joined at its endarea to a bar 60, particularly a support bar, that in turn is joined atits other end to the end area of the other second rib 61. The two bars60 are disposed in parallel and set apart from each other.

As described above, wall sections are conformed to the frame-likesupport section—formed thus of ribs 61, transverse ribs 62 and bars60—of housing top part 1, so that the shell-like housing top part isable to be formed in one piece, particularly as a casting.

In this connection, the wall sections, especially also two side wallsections 3 and the wall section having a concave-convex wave structure,are thus integrally molded and conformed to the frame-like supportsection and implemented in one piece.

Bars 60 stretch mainly in the horizontal direction, e.g., are extendedfurther horizontally than in any direction transverse to that.

The frame-like support section is thus realized by an increase in thewall thickness.

In addition, thickened areas are also provided on housing top part 1,which are intended as bearing mounting for at least one part, especiallyhalf, of the circumference of an outer ring of a bearing. Thesearch-like thickened areas adjoining one another are joined to transverseribs 62, especially in each case in that end area in which respectiverib 61 is joined.

The concave-convex wave structure of the wall sections enlarges thesurface area, and therefore reduces resistance to the transfer of heatto the ambient air. In this context, an especially sharp depression isprovided as depression 5 for a manipulation area for screw connections.In this case, the screws are connecting screws by which housing top part1 and housing bottom part 2 are screw-connected.

Housing bottom part 2 has a wave structure 6, particularly aconcave-convex wall section, which likewise enlarges the surface area,and therefore reduces resistance to the transfer of heat from thegear-unit interior, especially lubricating oil, to the ambient air.

The housing cover is provided to close an opening in housing top part 1,the opening being surrounded by the frame-shaped support section,especially with clearance. That means that the frame-shaped supportsection does not directly contact the opening, but rather is set apartfrom the opening.

As shown in FIG. 10, gear wheel 100 is joined in rotatably fixed mannerto shaft 101, which is supported in the housing by a bearing. In thiscontext, the bearing is accommodated in a bearing mounting in thehousing, a first part of the bearing mounting being located in housingtop part 1 and a second part of the bearing mounting being located inhousing bottom part 2.

The lower spatial area surrounding gear wheel 100 is enclosed by thetrough, the trough having side walls 102 and a bottom plate 103. Thus,it is able to be fabricated from three parts.

Side walls 102 of the trough are secured to bottom plate 103. At itslowest area, bottom plate 103 has a protuberance 130 directed downward.Protuberance 130 is directed radially away from the gear wheel, and isopen at its radially outer end area. Thus, lubricating oil of the gearunit gets from the oil pan of the gear unit through protuberance 130 upto gear wheel 100. Laterally, e.g., on both sides in the axialdirection, the protuberance is closed by a respective tab section 120 ofside walls 102, so that a channel is formed passing through radially togear wheel 100.

As illustrated in FIG. 12, in each case side walls 102 are punched outas a sheet-metal part, and at their axial outer side, have markingswhich identify the positions of bore holes to be introduced,particularly as a function of the transmission ratio of the gear unitand/or toothing data of gear wheel 100.

Screws are guided through the bore holes, making a screw connectionachievable between bottom plate 103 and respective side wall 102.

Therefore, depending on the size or other toothing data, the bottomplate is able to be positioned at an optimal radial distance from thecentral axis of the gear wheel.

Bottom plate 103 is likewise produced as a stamped bent part, and has aU-shaped cross-section. In this context, it is bent such that thedistance between the toothing, particularly the crowns of the teeth ofthe toothing of gear wheel 100 located in the same angle atcircumference as bottom plate 103, is constant. Thus, a narrow gap isprovided between these tooth crowns and bottom plate 103.

Consequently, a pumping action develops during rotational movement ofgear wheel 100, since the lubricating oil located in the tooth spaces ismoved with greater velocity than the lubricating oil in the channel. Inthis manner, lubricating oil is thus conveyed through the channel fromthe oil pan to gear wheel 100 and is then moved along with it.

The trough also reduces the losses due to splashing during movement ofgear wheel 100, for the teeth of the toothing of gear wheel 100 dip inthe spatial area surrounded by the trough.

With the exception of tab sections 120 and protuberance 130, U-shapedbottom plate 103 is bent circularly in the circumferential direction, sothat the distance between the teeth of the toothing of gear wheel 100and bottom plate 103 is substantially constant in the correspondingangle-at-circumference area.

Tab sections 120 are directed radially to the outside, so thatrespective side wall 102 is able to be pressed in the axial directiononto bottom plate 103, particularly at its tab sections 120, andscrew-connected.

With the aid of the pumping action of gear wheel 100 in interaction withthe trough, oil is pumped to a position situated higher than the oillevel of the oil pan, and from there is conducted via a temporarystorage or directly to the places to be lubricated, such as bearings orengaging gear teeth. Appropriate conduits or pipes are provided for thispurpose.

Protuberance 130 is able to be produced by bending out from the originalform of bottom plate 103. To that end, a punching sheet is bent suchthat two areas, bent in the shape of circle segments, are set apart fromeach other over an area bent substantially in the shape of a rectangle.After that, the areas bent in the shape of circle segments are pressedagainst each other, and thus form the circular area of bottom plate 103.At the same time, the areas bent in the shape of circle segmentsencompass an opening. The area bent in the shape of a rectangle likewisehas a centrally located opening and thus forms protuberance 130.

LIST OF REFERENCE NUMERALS

-   1 housing top part-   2 housing bottom part-   3 side wall section-   4 housing cover-   5 depression for manipulation area for screw connections-   6 wave structure, especially concave-convex wall section-   60 bar-   61 rib-   62 transverse rib-   63 lifting eyes-   90 oil level-   100 gear wheel-   101 shaft-   102 side wall-   103 bottom plate-   120 tab section-   130 protuberance

1-13. (canceled)
 14. A gear unit, comprising: a housing; and a troughadapted to guide oil and reduce losses due to splashing surrounding acircumferential section of a toothing part and/or a gear wheel, inradial and axial direction, the trough including at least three parts,including at least one bottom plate and two side walls, the bottom platebeing screw-connected to the two side walls, the trough being fastenedto the housing, the trough having an opening and/or a channel, at alowest surface area and/or at a surface area having a greatest radialdistance, during rotational movement of the tooting part and/or the gearwheel, oil being conveyed from an oil pan of the gear unit through theopening and/or the channel between the trough and the toothing and/orthe gear wheel, to a position higher than a level of the oil pan, thebottom plate and the side walls being stamped bent parts.
 15. The gearunit according to claim 14, wherein (a) a distance and/or (b) a distancein the radial direction, between the bottom plate and crowns of gearteeth of the gear unit is constant in a angle-at-circumference areacovered by the trough.
 16. The gear unit according to claim 14, whereinthe bottom plate includes tab sections extending in the radialdirection, at which the side walls are screw-connected.
 17. The gearunit according to claim 14, wherein one side wall includes a marking atwhich a bore hole is able to be placed for leading through a screw of ascrew connection.
 18. The gear unit according to claim 14, wherein theopening and/or the channel is bounded by the bottom plate and the twoside walls.
 19. The gear unit according to claim 14, wherein the bottomplate and each side wall are each formed in one piece.
 20. The gear unitaccording to claim 14, wherein the housing includes a housing top partand a housing bottom part, the housing top part having a frame-likesupport section on which wall sections are molded, the frame-likesupport section being formed integrally with the wall sections, as acasting and/or a steel casting.
 21. The gear unit according to claim 20,wherein a greatest wall thickness of the wall sections is less than thegreatest wall thickness of the support section.
 22. The gear unitaccording to claim 20, wherein the frame-like support section of thehousing top part includes a first and a second transverse rib and theframe-like support section includes two first ribs, the two first ribsbeing set apart from each other and in each case being joined to thefirst transverse rib at two points set apart from each other, the twosecond ribs being set apart from each other and in each case beingjoined to the second transverse rib at two points set apart from eachother.
 23. The gear unit according to claim 22, wherein the transverseribs extend mainly in a horizontal direction and/or extend further inthe horizontal direction than in any direction transverse to thehorizontal direction,
 24. The gear unit according to claim 22, whereinthe first ribs extend mainly in a vertical direction and/or extendfurther in the vertical direction than in any direction transverse tothe vertical direction.
 25. The gear unit according to claim 22, whereinthe second ribs extend mainly in the vertical direction and/or extendfurther in the vertical direction than in any direction transverse tothe vertical direction.
 26. The gear unit according to claim 22, whereineach first rib and each second rib includes a lifting eye at an end areafacing away from a respective transverse rib.
 27. The gear unitaccording to claim 22, wherein a first rib is joined at an end area to abar and/or a support bar, which is joined at another end to an end areaof a second rib, the other first rib being joined at an end area to abar and/or a support bar that is joined at another end to an end area ofthe other second rib.
 28. The gear unit according to claim 27, whereinthe bars are disposed in parallel and set apart from each other.
 29. Thegear unit according to claim 14, wherein a housing cover closes anopening in the housing top part, the opening being surrounded by theframe-shaped support section, with clearance, so that the frame-shapedsupport section does not directly contact the opening, but is set apartfrom the opening.
 30. The gear unit according to claim 22, wherein ashaft of the gear unit is supported by a bearing in the housing, a firstpart of the bearing mounting being located in a housing top part and asecond part of the bearing mounting being located in a housing bottompart, the first part of the bearing mounting including a thickenedsection, and being joined to an area of the transverse ribs at which therespective rib is also joined.